fix: surface ALL-scoped series breaks in provenance (#19)

.build_series_break_refs() matches `fin_code IN (<codes in the result>)`.
No row's item_code is ever the literal "ALL", so the four corpus-wide
entries could never match and reached no user:

  SB085  1977  dollar precision across the 1976/1977 boundary
  SB087  2002  imputation exclusion FY2002-2006
  SB194  2012  dense -> sparse representation change
  SB086  2017  government id scheme change

SB194 is why this matters now. cog_pipeline#64 DoD 4 was "series_breaks.csv
carries an ALL @ 2012 entry describing the representation change, SO
cog_explain() surfaces it". The entry shipped; the reader dropped it. A
query spanning FY2011 -> FY2012 crosses the boundary where an absent cell
stops meaning "Census published $0" and starts meaning "not reported", and
nothing said so.

Provenance gains `corpus_break_refs`, built by .build_corpus_break_refs()
on the break_year window alone -- which codes a result happens to contain
is irrelevant to a caveat about the corpus. A separate field rather than
more entries in series_break_refs, because an ALL caveat qualifies the
whole result and folding the two together invites reading it as a caveat
about one series; .build_series_break_refs() now excludes 'ALL' explicitly
so the two stay disjoint by construction. cog_explain() prints them under
their own "Corpus-wide caveats" heading, and cog-api passes provenance
through verbatim, so the field reaches the API with no change there.

On the year rule: all four entries are BOUNDARY caveats -- their own
join_advice speaks of crossing 1976/1977, of FY2002-2006, of absence not
being comparable across FY2012, of pre- vs post-2017 ids -- so the same
`break_year BETWEEN min(years) AND max(years)` rule the code-specific path
uses is the right one, and matches the issue's DoD 1. The issue's DoD 3
also asks that a FY2011 query surface SB085; that cannot hold under DoD 1
and does not hold under any reading of SB085's text, whose boundary is
1976/1977. Tested with a range that actually spans it, and flagged on the
issue.

Stacked on fix/regen-fixture-corpus-18: SB194 does not exist in main's
bundled fixture, which predates the break being catalogued.

Suite: 606 pass / 0 fail / 6 skip (was 594/0/6).
cog-api 357 / 0 / 8, unchanged.

tests/testthat/test-corpus-breaks.R

@@ -0,0 +1,94 @@
+# tests/testthat/test-corpus-breaks.R
+#
+# uscogdata#19. Four catalogued series breaks carry fin_code = "ALL" -- they
+# are caveats about the corpus itself rather than about one item code:
+#
+#   SB085  1977  dollar precision across the 1976/1977 boundary
+#   SB087  2002  imputation exclusion FY2002-2006
+#   SB194  2012  dense -> sparse representation change
+#   SB086  2017  government ID scheme change
+#
+# .build_series_break_refs() matches `fin_code IN (<codes in the result>)`,
+# and no row's item_code is ever the literal "ALL", so none of them could
+# ever reach a user. They now travel in their own provenance field,
+# `corpus_break_refs`, which keeps them distinguishable from the
+# code-specific `series_break_refs` (an ALL caveat qualifies the whole
+# result, not one series).
+
+test_that("corpus_break_refs surfaces an ALL-scoped break the year range spans", {
+  skip_if_no_corpus()
+  with_fixture_corpus({
+    # SB194 sits at FY2012 -- the dense/sparse boundary. A query spanning
+    # 2011 -> 2012 straddles it, and this is the case cog_pipeline#64's
+    # DoD 4 intended to reach users.
+    r <- cog_spending("121011212191", 2011:2012, "Police")
+    prov <- attr(r, "provenance")
+    expect_true("SB194" %in% prov$corpus_break_refs)
+  })
+})
+
+test_that("corpus_break_refs stays empty when no ALL break falls in the range", {
+  skip_if_no_corpus()
+  with_fixture_corpus({
+    # 2019-2020 spans no catalogued corpus-wide break.
+    r <- cog_spending("121011212191", 2019:2020, "Police")
+    expect_equal(attr(r, "provenance")$corpus_break_refs, character(0))
+  })
+})
+
+test_that("corpus_break_refs and series_break_refs stay disjoint", {
+  skip_if_no_corpus()
+  with_fixture_corpus({
+    r <- cog_spending("121011212191", 2011:2012, "Police")
+    prov <- attr(r, "provenance")
+    expect_type(prov$series_break_refs, "character")
+    expect_type(prov$corpus_break_refs, "character")
+    # An ALL caveat must never masquerade as a break in a specific series.
+    expect_length(intersect(prov$series_break_refs, prov$corpus_break_refs), 0L)
+    expect_false("SB194" %in% prov$series_break_refs)
+  })
+})
+
+test_that(".build_corpus_break_refs matches on the break_year window alone", {
+  skip_if_no_corpus()
+  con <- cog_open()
+  on.exit(cog_close())
+
+  # SB085's boundary is 1976/1977, outside the fixture's partitions -- the
+  # series_breaks table is a full cross-vintage registry, so the matching
+  # logic is testable there even though no long partition covers it.
+  expect_true("SB085" %in% uscogdata:::.build_corpus_break_refs(
+    con, years = 1975:1980, schema_version = 6L
+  ))
+  # ... and does not fire for a range that misses it, unlike a filter keyed
+  # on the era rather than the boundary.
+  expect_false("SB085" %in% uscogdata:::.build_corpus_break_refs(
+    con, years = 1978:1980, schema_version = 6L
+  ))
+
+  # Unlike code-specific refs, these do not depend on which codes a result
+  # happens to contain -- that dependency is the whole defect.
+  expect_setequal(
+    uscogdata:::.build_corpus_break_refs(con, years = 2001:2003, schema_version = 6L),
+    "SB087"
+  )
+
+  # Gated on schema_version >= 5: series_breaks_pq is not registered below it.
+  expect_equal(
+    uscogdata:::.build_corpus_break_refs(con, years = 2011:2012, schema_version = 4L),
+    character(0)
+  )
+})
+
+test_that("cog_explain() prints corpus-wide caveats under their own heading", {
+  skip_if_no_corpus()
+  with_fixture_corpus({
+    r <- cog_spending("121011212191", 2011:2012, "Police")
+    out <- paste(c(
+      capture.output(cog_explain(r)),
+      capture.output(cog_explain(r), type = "message")
+    ), collapse = "\n")
+    expect_match(out, "Corpus-wide caveats", fixed = TRUE)
+    expect_match(out, "SB194", fixed = TRUE)
+  })
+})